• This community needs YOUR help today. We rely 100% on Supporting Memberships to fund our efforts. With the ever increasing fees of everything, we need help. We need more Supporting Members, today. Please invest back into this community. I will ship a few decals too in addition to all the account perks you get.



    Sign up here: https://www.muzzleloadingforum.com/account/upgrades

Cook Bros. lock problem

Muzzleloading Forum

Help Support Muzzleloading Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

snubnose57

40 Cal.
Joined
Jul 23, 2010
Messages
194
Reaction score
8
My rifle's hammer falls to half cock when I pull the trigger. Removed the lock and saw nothing unusual. Would take a picture, but not savvy enough to know how, PC challenged. Did a forum search with no hits. Not sure what to do??
 
Thanks, not sure which screw that is. There are 2 on what I think is the bridle, and one above a small v'spring on the back of the lock. I loosened all 3 with no luck.
 
Does your gun have double set triggers?

If it does, there must be a "fly" in the lock to block off the tumblers half cock notch when the hammer falls from the full cock position.

By blocking off the half cock notch, the sear which releases the tumbler and allows the hammer to fall, will bump into the fly and jump over it allowing the hammer to fall to the fired position.

Occasionally, a fly, which is a very small part, will get gummed up with semi-dried oil so that it does not move freely as it should.
 
snubnose57 said:
Thanks, not sure which screw that is. There are 2 on what I think is the bridle, and one above a small v'spring on the back of the lock. I loosened all 3 with no luck.

I mean the lockplate screw. If it's too tight, it can cause problems. It's the simplest thing to test, if not, then you can delve more deeply.
 
I will be watching this thread! I have one same thing but mine will fire. Only problem is its got about a 55lb trigger now :shocked2: Gonna screw with it a bit more then off to a member that offered to inspect. Our members are the BEST :)
 
I wonder if this may be a trigger problem, not lock. Maybe the trigger bar(?) is not pushing the sear arm up enough to override the half cock notch.
 
Although I shouldn't laugh I could jinx myself plus I have couple close friends in law enforcement there, that aren't exempt from the 10 lbs trigger requirement and am interested in you guys solving your issues...

:pop:
 
Just to clear things, this is a lock from a rifled musket, thus only one trigger. Hope this description helps.
 
Thank you.

I hate to say it but perhaps the problem is the method you are using for pulling the trigger?

Rifled muskets usually had a heavy trigger pull.
It was intended to keep the soldier from inadvertently firing the gun.
It also caused the trigger finger to continue pulling the trigger rearward after the sear was released from the full cock notch in the tumbler.

This usually causes the nose of the sear to be lifted well clear of the tumbler by the time the half cock notch sweeps past it so, the sear catching in the half cock notch rarely happened.

If you are using just enough pull on the trigger to release the sear but not really trying to pull the trigger fully to the rear, this could cause the problem.
You might want to try firing the gun by giving the trigger a stout, full pull and see if that doesn't fix the problem.

If it doesn't, removing a bit of material at the half cock to add some extra clearance with the nose of the sear might be needed.

If you do this, be careful. The little hook that traps the nose of the sear must have some thickness to it or it might break off.
 
Thanks, but pulling the trigger as hard and fast as I can, still falls to half cock every time. Just wondering, would the small spring above the trigger prevent the sear from rising up enough to clear the half cock notch?
 
If this is a Dixie Gunworks gun I suggest you contact them for repair before you try to fix it.
 
No, it is a used Euroarms. Got it for cheap, knowing the problem. Was hoping to fix it myself, and learn something along the way.
 
It sounds to me an amateur tried to give it a trigger job before you got it.

The sear catching in the safety notch can occur by trying to get a better non-creepy trigger. The tumblers main sear area was most likley longer on the face than the sear tip and the tip had to be pulled down a bit to get the tumbler to break from engagement. At that time the sear tip was past the face plane of the safety notch and would have gone past the notch.

However removal of the edge so the notch fit the sear tip was taken from the tumblers face instead of building the bottom of the notch up putting the sear tip closer to the edge.

Not being the best at writing I hope that explained it some here will get where I was going with it and can even make a sketch showing why. Many Smithing books explain this problem and not just the ML ones. It is a common problem of trigger work creating the problem you have.

The easiest fix is a new tumbler if you can find one or tig welding the tumbler shelf higher and stoneing the sear section again.
 
Occasionally, a fly, which is a very small part, will get gummed up with semi-dried oil so that it does not move freely as it should.

And/or fall out during cleaning and get lost. Sometimes without the owner even noticing it.
DAMHIK :redface:

Seriously, take a look for a possibly missing fly. If you don't know what it is do a search for pics of lock internals.
 
snubnose57 said:
My rifle's hammer falls to half cock when I pull the trigger. Removed the lock and saw nothing unusual. Would take a picture, but not savvy enough to know how, PC challenged. Did a forum search with no hits. Not sure what to do??
I bought a used 1853 from a fellow that also had a hard trigger pull and hammer would sometime fall in the half cock notch of the tumbler. I replaced the sear spring with a lighter one and it solved my heavy pull and also my hammer fall. The original sear spring portion that contacted the sear was too long and pushing into the sear portion where the sear screw goes through preventing the spring to flex. have a look in that area you might have that issue also :hmm: :v - just my two cents worth :idunno: :grin: .
 
Back
Top